Some people are actually already voting. Early voting is underway in several states, and today Iowa joins that club. In total, 34 states allow early voting in one form or another. It's becoming a much more popular option with each election, and we wanted to learn more, so we reached Paul Gronke. He's director of the Early Voting Information Center at Reed College. Professor Gronke, welcome to the program.

PAUL GRONKE: Thank you. Good morning.

GREENE: Tell me what percentage of the vote you expect to be cast early this year, and I guess how it compares to elections in the past.

GRONKE: Well, surprisingly enough, we can't get a precise figure, particularly if we go back in time, because states didn't report the breakdowns. The best estimates from 2008 are between 30 and 33 percent of voters cast a ballot prior to Election Day. That compares to about 20 percent back in 2004, and then 15 percent in 2000.

GREENE: And how big are we expected to get this year?

GRONKE: Well, again, there's some disagreements. Some states have ratcheted back early voting, but as voters choose this method, they tend to continue, and others flock to it, so somewhere around 35 percent is the best estimate.

GREENE: How have campaigns adapted their strategy to this reality?

GRONKE: I think campaigns have to mobilize over a longer period of time. We don't really know whether, you know, those last minute bombshells that you drop just before the 5:00 p.m. news on Monday to hit that Monday news cycle and don't allow your opponent a time to react - we don't know whether they're retiming those or not, but you would think that you can't wait after one-third of the electorate is voted to drop that information.

GREENE: You know, one other thing I wonder, Professor Gronke, is there a profile of an early voter? I mean, do more Democrats or more Republicans tends to vote earlier?

GRONKE: Well, there has been a profile and it's been the decided. So it's been both Democrats and Republicans, but it's been those who've made up their mind. So if you look on one side of the coin, they're partisan, they're ideological, and you flip that coin over and you see the kind of patterns we've seen for a long time in American politics. Better educated, higher income, and these have tended toward Republicans, but as the early electorate has expanded, it's also diversified.

Particularly in 2008, we saw African-Americans flock to the early in-person polls in the southeastern part of the United States, and that really fits right in. I mean, when Barack Obama was nominated in 2008, really for a lot of African Americans in North Carolina, Florida, Georgia, they could have cast their ballot right there. There was very little that was going to make them vote for John McCain.

GREENE: Being the director of the Early Voting Information Center, you've actually been called as an expert witness by the Justice Department in a legal challenge in Florida. I think the issue is a law that would limit early voting. What exactly is being debated there, and where to things stand?

GRONKE: Well, during 2008 and afterwards, African-Americans used early in-person voting at higher rates than whites in Florida, and in the five counties that are the covered counties under Section 5 of the Voting Rights Act, the state of Florida has to actually positively show that African-Americans will not be harmed by these changes, and that's very difficult because you're projecting into the future. So that was really the point of the litigation.

GREENE: Let me just make sure I understand that point, because it sounds it a bit complicated, but important. The Justice Department is responsible for some counties in Florida based on civil rights legislation, and if they believe limiting early voting hurts African-Americans, it's their job to make sure the law doesn't come into play. Where do things stand? Is it still an issue right now?

GRONKE: It is not an issue anymore in Florida. They've reached a settlement where the number of hours are the same as it was in 2008, and the five covered counties in Florida have agreed to offer early voting the same amount of time as the rest of the state.

GREENE: Political science professor Paul Gronke is director of the Early Voting Information Center at Reed College. Thanks so much for joining us, Professor.